Baseline Data: Sex Differences In Human Performance

Animal studies clearly demonstrate a bidirectional relationship between the gut microbiota and exercise capacity. While animal models show mechanistic links, there is a lack of translating these findings to humans. PURPOSE: Determine if exercise performance is influenced by the gut microbiota and its perturbation with antibiotics (ABX) in humans. We present baseline performance data in men and women. METHODS: Healthy recreationally active males (n = 10) and females (n = 8, on hormonal contraceptives) aged 18-40 yrs were recruited. Participants completed a VO2max assessment, standardized treadmill warm-up consisting of three 8-minute stages at 5, 6, and 7 mph, followed by a 5 km treadmill time trial. Body composition (air plethysmography), relative VO2, RER and RPE were collected. RESULTS: Participants were 26.1 ± 6.42 and 27.37 ± 5.40 yrs for males and females respectively. Height (176.04 ± 7.33 vs 161.60 ± 8.24 cm, p < 0.05) and body mass (77.44 ± 7.89 vs 59.86 ± 10.61 kg, p < 0.05) were significantly greater in males while body fat percentage (12.91 ± 6.48 vs 18.68 ± 8.16%, p = 0.11) was not significantly different between the sexes. Relative VO2max was significantly greater in males compared to females (54.1 ± 5.28 vs 46.10 ± 5.19 ml/kg/min, p < .05) while RPE for all stages of the warm-up was not significantly different between sexes. Time to 50% carbohydrate (CHO) utilization (RER = .85 and no lesser for the remainder of the warmup) was lower in males compared to females (4.15 ± 2.29 vs 6.78 ± 6.37 min) but not statistically significant. Interestingly, one male and two female participants reached 100% CHO utilization (RER = 1 and no lesser for the remainder of the warmup). Interestingly, one of these females had the highest relative VO2max and the other had the lowest within females while the male had the lowest VO2max within males (54.7, 37.3, and 46.3 ml/kg/min respectively). Finally, five-kilometer time was significantly faster in males (24.27 ± 4 vs 28.1 ± 4.65 min, p < .05). CONCLUSION: This data suggests some standard sex differences with males being taller and having greater body mass and 5 km performance, however, there are no sex differences between body composition and fuel utilization. This data will be compared to post-ABX treatment data to uncover if ABX impact exercise performance. Supported by: Supported by the Rutgers NExT Center / New Jersey Institute of Food, Nutrition, and Health Small Grant